Composition for odor suppression

ABSTRACT

A composition for odor control includes (A) from 85 wt % to 99.5 wt % of an olefin-based compound and (B) from 15 wt % to 0.5 wt % of an odor suppressant. The odor suppressant includes a blend of (i) an ionomer, (ii) particles of zinc oxide, and (iii) particles of copper oxide. The composition has a methyl mercaptan odor suppression value of greater than 45% as measured in accordance with ASTM D5504-12.

BACKGROUND

Many uses of articles made from olefin-based polymer encounter thenuisance of foul odor. Common sources of offending odor include hydrogensulfide (H₂S) emitting compositions and mercaptan-containingcompositions. Many applications exist where it is desirable for anolefin-based polymer article to be able to remove, or otherwisesuppress, odor. As such, numerous industries desire materials that canremove sulfur-based odorants such as H₂S and mercaptans, from the gasphase. A common example is the ability of a plastic trash bag liner(i.e., an olefin-based polymer article) to be able to remove odor.

Metal oxides such as zinc oxide (ZnO) particles, and zinc salts inparticular, are known to consume many odor-generating molecules such asH₂S and mercaptans. All other factors being equal, it is known that ZnOconcentration and odor suppression are directly related—i.e., as ZnOconcentration increases in a given olefin-based polymer article, theeffectiveness of odor suppression also increases.

Although odor suppression increases as metal oxide (ZnO in particular)increases, limits do exist for the amount of ZnO that can be effectivelyincorporated into olefin-based polymer articles. In the production ofblown film trash liners for example, high loading of ZnO particlesincreases extrusion die lip buildup, thereby causing film defects. Highloading of ZnO particles also increases haze resulting in degradation ofolefin-based polymer film transparency and/or degradation in film color.High loading of ZnO particles also deleteriously impacts mechanicalproperties such as impact strength and film tear strength. Processingparameters and end-use mechanical requirements thereby impose practicallimits to the load of ZnO particles into olefin-based polymercompositions.

A need therefore exists for olefin-based polymer compositions withimproved odor suppression while simultaneously carrying suitable metaland/or zinc load in order to maintain processability, desired optics,and desired mechanical properties for end-use applications. A needfurther exists for odor-suppressing articles made from such olefin-basedpolymer compositions.

SUMMARY

The present disclosure provides a composition. In an embodiment, acomposition for odor control is provided and includes (A) from 85 wt %to 99.5 wt % of an olefin-based compound and (B) from 15 wt % to 0.5 wt% of an odor suppressant. The odor suppressant includes a blend of (i)an ionomer, (ii) particles of zinc oxide, and (iii) particles of copperoxide. The composition has a methyl mercaptan odor suppression value ofgreater than 45% as measured in accordance with ASTM D5504-12.

Definitions

Any reference to the Periodic Table of Elements is that as published byCRC Press, Inc., 1990-1991. Reference to a group of elements in thistable is by the new notation for numbering groups.

For purposes of United States patent practice, the contents of anyreferenced patent, patent application or publication are incorporated byreference in their entirety (or its equivalent U.S. version is soincorporated by reference) especially with respect to the disclosure ofdefinitions (to the extent not inconsistent with any definitionsspecifically provided in this disclosure) and general knowledge in theart.

The numerical ranges disclosed herein include all values from, andincluding, the lower and upper value. For ranges containing explicitvalues (e.g., 1 or 2, or 3 to 5, or 6, or 7), any subrange between anytwo explicit values is included (e.g., the range 1-7 above includessubranges of 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6; etc.).

Unless stated to the contrary, implicit from the context, or customaryin the art, all parts and percents are based on weight and all testmethods are current as of the filing date of this disclosure.

An “agglomerate” is a plurality of individual fine solid particlesclumped or otherwise together forming a single mass.

The terms “blend” or “polymer blend,” as used herein, is a blend of twoor more polymers. Such a blend may or may not be miscible (not phaseseparated at molecular level). Such a blend may or may not be phaseseparated. Such a blend may or may not contain one or more domainconfigurations, as determined from transmission electron spectroscopy,light scattering, x-ray scattering, and other methods known in the art.

The term “composition” refers to a mixture of materials which comprisethe composition, as well as reaction products and decomposition productsformed from the materials of the composition.

The terms “comprising,” “including,” “having” and their derivatives, arenot intended to exclude the presence of any additional component, stepor procedure, whether or not the same is specifically disclosed. Inorder to avoid any doubt, all compositions claimed through use of theterm “comprising” may include any additional additive, adjuvant, orcompound, whether polymeric or otherwise, unless stated to the contrary.In contrast, the term “consisting essentially of” excludes from thescope of any succeeding recitation any other component, step, orprocedure, excepting those that are not essential to operability. Theterm “consisting of” excludes any component, step, or procedure notspecifically delineated or listed. The term “or,” unless statedotherwise, refers to the listed members individually as well as in anycombination. Use of the singular includes use of the plural and viceversa.

An “ethylene-based polymer” is a polymer that contains more than 50weight percent (wt %) polymerized ethylene monomer (based on the totalamount of polymerizable monomers) and, optionally, may contain at leastone comonomer. Ethylene-based polymer includes ethylene homopolymer, andethylene copolymer (meaning units derived from ethylene and one or morecomonomers). The terms “ethylene-based polymer” and “polyethylene” maybe used interchangeably. Non-limiting examples of ethylene-based polymer(polyethylene) include low density polyethylene (LDPE) and linearpolyethylene. Non-limiting examples of linear polyethylene includelinear low density polyethylene (LLDPE), ultra-low density polyethylene(ULDPE), very low density polyethylene (VLDPE), multi-componentethylene-based copolymer (EPE), ethylene/α-olefin multi-block copolymers(also known as olefin block copolymer (OBC)), substantially linear, orlinear, plastomers/elastomers, and high density polyethylene (HDPE).Generally, polyethylene may be produced in gas-phase, fluidized bedreactors, liquid phase slurry process reactors, or liquid phase solutionprocess reactors, using a heterogeneous catalyst system, such asZiegler-Natta catalyst, a homogeneous catalyst system, comprising Group4 transition metals and ligand structures such as metallocene,non-metallocene metal-centered, heteroaryl, heterovalent aryloxyether,phosphinimine, and others. Combinations of heterogeneous and/orhomogeneous catalysts also may be used in either single reactor or dualreactor configurations.

“Ethylene plastomers/elastomers” are substantially linear, or linear,ethylene/α-olefin copolymers containing homogeneous short-chainbranching distribution comprising units derived from ethylene and unitsderived from at least one C₃-C₁₀ α-olefin comonomer. Ethyleneplastomers/elastomers have a density from 0.870 g/cc to 0.917 g/cc.Non-limiting examples of ethylene plastomers/elastomers includeAFFINITY™ plastomers and elastomers (available from The Dow ChemicalCompany), EXACT™ Plastomers (available from ExxonMobil Chemical),Tafmer™ (available from Mitsui), Nexlene™ (available from SK ChemicalsCo.), and Lucene™ (available LG Chem Ltd.).

“High density polyethylene” (or “HDPE”) is an ethylene homopolymer or anethylene/α-olefin copolymer with at least one C₄-C₁₀ α-olefin comonomer,or C₄-C₈ α-olefin comonomer and a density from 0.940 g/cc, or 0.945g/cc, or 0.950 g/cc, 0.953 g/cc to 0.955 g/cc, or 0.960 g/cc, or 0.965g/cc, or 0.970 g/cc, or 0.975 g/cc, or 0.980 g/cc. The HDPE can be amonomodal copolymer or a multimodal copolymer. A “monomodal ethylenecopolymer” is an ethylene/C₄-C₁₀ α-olefin copolymer that has onedistinct peak in a gel permeation chromatography (GPC) showing themolecular weight distribution. A “multimodal ethylene copolymer” is anethylene/C₄-C₁₀ α-olefin copolymer that has at least two distinct peaksin a GPC showing the molecular weight distribution. Multimodal includescopolymer having two peaks (bimodal) as well as copolymer having morethan two peaks. Non-limiting examples of HDPE include DOW™ High DensityPolyethylene (HDPE) Resins (available from The Dow Chemical Company),ELITE™ Enhanced Polyethylene Resins (available from The Dow ChemicalCompany), CONTINUUM™ Bimodal Polyethylene Resins (available from The DowChemical Company), LUPOLEN™ (available from LyondellBasell), as well asHDPE products from Borealis, Ineos, and ExxonMobil.

An “interpolymer” is a polymer prepared by the polymerization of atleast two different monomers. This generic term includes copolymers,usually employed to refer to polymers prepared from two differentmonomers, and polymers prepared from more than two different monomers,e.g., terpolymers, tetrapolymers, etc.

“Linear low density polyethylene” (or “LLDPE”) is a linearethylene/α-olefin copolymer containing heterogeneous short-chainbranching distribution comprising units derived from ethylene and unitsderived from at least one C₃-C₁₀ α-olefin, or C₄-C₈ α-olefin, comonomer.LLDPE is characterized by little, if any, long chain branching, incontrast to conventional LDPE. LLDPE has a density from 0.910 g/cc toless than 0.940 g/cc. Non-limiting examples of LLDPE include TUFLIN™linear low density polyethylene resins (available from The Dow ChemicalCompany), DOWLEX™ polyethylene resins (available from the Dow ChemicalCompany), and MARLEX™ polyethylene (available from Chevron Phillips).

“Low density polyethylene” (or “LDPE”) consists of ethylene homopolymer,or ethylene/α-olefin copolymer comprising at least one C₃-C₁₀ α-olefin,or C₄-C₈ α-olefin, that has a density from 0.915 g/cc to less than 0.940g/cc and contains long chain branching with broad MWD. LDPE is typicallyproduced by way of high pressure free radical polymerization (tubularreactor or autoclave with free radical initiator). Non-limiting examplesof LDPE include MarFlex™ (Chevron Phillips), LUPOLEN™ (LyondellBasell),as well as LDPE products from Borealis, Ineos, ExxonMobil, and others.

“Multi-component ethylene-based copolymer” (or “EPE”) comprises unitsderived from ethylene and units derived from at least one C₃-C₁₀α-olefin, or C₄-C₈ α-olefin, comonomer, such as described in patentreferences U.S. Pat. Nos. 6,111,023; 5,677,383; and 6,984,695. EPEresins have a density from 0.905 g/cc to 0.962 g/cc. Non-limitingexamples of EPE resins include ELITE™ enhanced polyethylene (availablefrom The Dow Chemical Company), ELITE AT™ advanced technology resins(available from The Dow Chemical Company), SURPASS™ Polyethylene (PE)Resins (available from Nova Chemicals), and SMART™ (available from SKChemicals Co.).

An “olefin-based polymer” or “polyolefin” is a polymer that containsmore than 50 weight percent polymerized olefin monomer (based on totalamount of polymerizable monomers), and optionally, may contain at leastone comonomer. Non-limiting examples of an olefin-based polymer includeethylene-based polymer or propylene-based polymer.

A “polymer” is a compound prepared by polymerizing monomers, whether ofthe same or a different type, that in polymerized form provide themultiple and/or repeating “units” or “mer units” that make up a polymer.The generic term polymer thus embraces the term homopolymer, usuallyemployed to refer to polymers prepared from only one type of monomer,and the term copolymer, usually employed to refer to polymers preparedfrom at least two types of monomers. It also embraces all forms ofcopolymer, e.g., random, block, etc. The terms “ethylene/α-olefinpolymer” and “propylene/α-olefin polymer” are indicative of copolymer asdescribed above prepared from polymerizing ethylene or propylenerespectively and one or more additional, polymerizable α-olefin monomer.It is noted that although a polymer is often referred to as being “madeof” one or more specified monomers, “based on” a specified monomer ormonomer type, “containing” a specified monomer content, or the like, inthis context the term “monomer” is understood to be referring to thepolymerized remnant of the specified monomer and not to theunpolymerized species. In general, polymers herein are referred to hasbeing based on “units” that are the polymerized form of a correspondingmonomer.

A “propylene-based polymer” is a polymer that contains more than 50weight percent polymerized propylene monomer (based on the total amountof polymerizable monomers) and, optionally, may contain at least onecomonomer. Propylene-based polymer includes propylene homopolymer, andpropylene copolymer (meaning units derived from propylene and one ormore comonomers). The terms “propylene-based polymer” and“polypropylene” may be used interchangeably. Non-limiting examples ofsuitable propylene copolymer include propylene impact copolymer andpropylene random copolymer.

“Ultra-low density polyethylene” (or “ULDPE”) and “very low densitypolyethylene” (or “VLDPE”) each is a linear ethylene/α-olefin copolymercontaining heterogeneous short-chain branching distribution comprisingunits derived from ethylene and units derived from at least one C₃-C₁₀α-olefin comonomer. ULDPE and VLDPE each has a density from 0.885 g/ccto 0.915 g/cc. Non-limiting examples of ULDPE and VLDPE include ATTANE™ultra low density polyethylene resins (available from The Dow ChemicalCompany) and FLEXOMER™ very low density polyethylene resins (availablefrom The Dow Chemical Company).

Test Methods

D10, D50, and D90 particle size is measured using a Coulter LS 230 LaserLight Scattering Particle Sizer, available from Coulter Corporation. D10particle size is the particle diameter at which 10% of the powder's massis composed of particles with a diameter less than this value. D50particle size is the particle diameter at which 50% of the powder's massis composed of particles with a diameter less than this value and 50% ofthe powder's mass is composed of particles with a diameter greater thansaid value. D90 particle size is the particle diameter at which 90% ofthe powder's mass is composed of particles with a diameter less thanthis value. Mean volume average particle size is measured using aCoulter LS 230 Laser Light Scattering Particle Sizer, available fromCoulter Corporation. Particle size distribution is calculated inaccordance with Equation A:

$\begin{matrix}{{Particle}\mspace{14mu}{size}\mspace{14mu}{distribution}{{= \frac{\left( {{D90} - {D10}} \right)}{D50}}.}} & {{Equation}\mspace{14mu} A}\end{matrix}$

Dart impact strength is measured in accordance with ASTM D1709, withresults reported in grams (g).

Density is measured in accordance with ASTM D792, Method B. The resultis recorded in grams per cubic centimeter (g/cc).

Differential Scanning Calorimetry (DSC). Differential ScanningCalorimetry (DSC) can be used to measure the melting, crystallization,and glass transition behavior of a polymer over a wide range oftemperature. For example, the TA Instruments Q1000 DSC, equipped with anRCS (refrigerated cooling system) and an autosampler is used to performthis analysis. During testing, a nitrogen purge gas flow of 50 ml/min isused. Each sample is melt pressed into a thin film at about 175° C.; themelted sample is then air-cooled to room temperature (about 25° C.). A3-10 mg, 6 mm diameter specimen is extracted from the cooled polymer,weighed, placed in a light aluminum pan (ca 50 mg), and crimped shut.Analysis is then performed to determine its thermal properties.

The thermal behavior of the sample is determined by ramping the sampletemperature up and down to create a heat flow versus temperatureprofile. First, the sample is rapidly heated to 180° C. and heldisothermal for 3 minutes in order to remove its thermal history. Next,the sample is cooled to −40° C. at a 10° C./minute cooling rate and heldisothermal at −40° C. for 3 minutes. The sample is then heated to 180°C. (this is the “second heat” ramp) at a 10° C./minute heating rate. Thecooling and second heating curves are recorded. The cool curve isanalyzed by setting baseline endpoints from the beginning ofcrystallization to −20° C. The heat curve is analyzed by settingbaseline endpoints from −20° C. to the end of melt. The valuesdetermined are extrapolated onset of melting, Tm, and extrapolated onsetof crystallization, Tc. Heat of fusion (H_(f)) (in Joules per gram), andthe calculated % crystallinity for polyethylene samples using thefollowing Equation: % Crystallinity=((H_(f))/292 J/g)×100. Glasstransition temperature, Tg, is determined from the DSC heating curvewhere half the sample has gained the liquid heat capacity as describedin Bernhard Wunderlich, The Basis of Thermal Analysis, in ThermalCharacterization of Polymeric Materials 92, 278-279 (Edith A. Turi ed.,2d ed. 1997). Baselines are drawn from below and above the glasstransition region and extrapolated through the Tg region. Thetemperature at which the sample heat capacity is half-way between thesebaselines is the Tg.

Elmendorf tear (or tear) is measured in accordance with ASTM D1922-15,machine direction (MD), with results reported in grams-force (gf).

Melt flow rate (MFR) in g/10 min is measured in accordance with ASTMD1238 (230° C./2.16 kg).

Melt index (MI) (12) in g/10 min is measured in accordance with ASTMD1238 (190° C./2.16 kg).

Odor Suppression/Odor Suppression Value.

Odor suppression is the ability of a composition to neutralize, orotherwise reduce, the amount of volatile sulfur-containing compounds. Inthe present disclosure, the odor suppression for methyl mercaptan ismeasured with gas chromatography equipped with an Agilent SulfurChemiluminescence Detector (GC-SCD) in accordance with ASTM D5504-12. Acontrol sample is prepared by placing a film formed from DOWLEX 2085G,ethylene/octene LLDPE, into a Tedlar® bag (polyvinyl fluoride). TheTedlar® bag for the control is subsequently filled with 900 mL of heliumgas and known amount of methyl mercaptan and the Tedlar® bag is closed.Test samples are prepared by placing a film formed from respective testcompositions, each test film placed into a respective Tedlar® bag. EachTedlar® bag is subsequently filled with 900 mL of helium gas and knownamount of methyl mercaptan, and the Tedlar® bag is closed. Samples areinjected onto the GC-SCD at pre-determined time intervals from each bagin order to evaluate odor suppression capability.

The reference samples and test samples were analyzed after two days. Thereference sample was used as the calibration standard to calculate themethyl mercaptan concentration of each test sample.

A. Sample Preparation

The control sample and each test sample containing 5 ppmv methylmercaptan were prepared in SKC 1 L sample bag (SKC Tedlar® Sample Bag, 1Liter, Cat No. 232-01). A reference sample without a film was preparedin a Tedlar® bag as the calibration standard.

1. Cut 1.0 g of film into strips (approximately 1 cm×30 cm).

2. Unscrew the valve from the sample bag, insert the film strips intothe bag through the valve opening with the handle of cotton tippedapplicator, and install the valve back to the sample bag, squeeze airout of bag before tightening the valve to seal the bag.3. Fill the bag with 0.90 L of helium gas (AirGas, Ultra Grade Helium).4. Inject 50 mL of 100 ppmv methyl mercaptan, into the bag using agas-tight glass syringe.

The odor suppression value test can also be performed for otherodorants, including ethyl mercaptan, propyl mercaptan, and butylmercaptan.

B. GC-SCD Conditions

-   -   1 Gas chromatograph: Agilent Model 7890 with a split/splitless        injection port, available from Agilent Technologies, 2850        Centerville Road, Wilmington, Del. 19808.    -   2. Detector: Agilent Sulfur Chemiluminescence (SCD), Model        G6644A.    -   3. Chromatography data system: Agilent OpenLAB software.    -   4. Columns: Agilent J&W DB-1 30 m×0.32 mm ID, 5 μm film        thickness.    -   5. Carrier Gas: Hydrogen, constant flow mode, 2.0 ml/min.    -   6. Inlet: Split, temperature: 250° C., split ratio: 100:1.    -   7. Injection volume: 500 μL by Valco Six Port Valve, Loop Size:        500 μL.    -   8. Oven Temperature: 30° C. hold for 1 minute, 15° C./min to        140° C., hold for 1 minutes.    -   9. SCD Detector Conditions:    -   Temperature: 250° C.    -   Hydrogen Flow: 38.3 mL/min.    -   Oxidizer Flow: 59.9 sccm.    -   Pressure: 400 Torr.    -   An odor suppression value (OSV) is the removal % of methyl        mercaptan calculated by the following equation:

${OSV} = {{\frac{\begin{matrix}{{{Concentration}\mspace{14mu}{of}\mspace{14mu}{Reference}\mspace{14mu}{Sample}} -} \\{{Concentration}\mspace{14mu}{of}\mspace{14mu}{Test}\mspace{14mu}{Sample}}\end{matrix}}{{Concentration}\mspace{14mu}{of}\mspace{14mu}{Reference}\mspace{14mu}{Sample}} \times 100} = {\frac{\begin{matrix}{{{Peak}\mspace{14mu}{Area}\mspace{14mu}{of}\mspace{14mu}{Reference}\mspace{14mu}{Sample}} -} \\{{Peak}\mspace{14mu}{Area}\mspace{14mu}{of}\mspace{14mu}{Test}\mspace{14mu}{Sample}}\end{matrix}}{{Peak}\mspace{14mu}{Area}\mspace{14mu}{of}\mspace{14mu}{Reference}\mspace{14mu}{Sample}} \times 100}}$

The Peak Area is the response of GC-SCD.

A non-limiting example of OSV calculation is provided. At two days theGC-SCD peak area of methylmercaptan in the reference sample is 28240298,whereas the GC-SCD peak area of methyl mercaptan in the test sample IE 1is 5667327 (unit is pA*s in Agilent OpenLAB software). The odorsuppression value for the test sample IE 1 is(((28240298-5667327)/28240298)*100=80. As shown in the equation of OSV,both concentration of methyl mercaptan and GC-SCD Peak Area of methylmercaptan can be used to calculate OSV.

Porosity and Surface Area. Brunauer-Emmett-Teller (BET) porosity andsurface area analysis are performed using a Micromeritics AcceleratedSurface Area & Porosimetry instrument (ASAP 2420). The sample isout-gassed at 105° C. while under vacuum prior to analysis.

The ASAP 2420 instrument employs a static (volumetric) method of dosingsamples and measures the quantity of gas that can be physically adsorbed(physisorbed) on a solid at liquid nitrogen temperature. For themulti-point BET measurement the volume of nitrogen uptake is measured atpre-selected relative pressure points at constant temperature. Therelative pressure is the ratio of the applied nitrogen pressure to thevapor pressure of nitrogen at the analysis temperature of 77 Kelvin (K).Results for porosity are reported in cubic meters per gram, or m³/g.Results for surface area are reported in square meters per gram, orm²/g.

Zinc/copper-total amount. The total amount of zinc and/or copper presentin a composition is determined with x-ray fluorescence spectrometry(XRS), in accordance with ASTM D6247. Results are reported in parts permillion, or ppm.

DETAILED DESCRIPTION

The present disclosure provides a composition. In an embodiment, acomposition for suppressing odors is provided and includes (A) from 85wt % to 99.5 wt % of an olefin-based polymer and (B) from 15 wt % to 0.5wt % of an odor suppressant. The odor suppressant is a blend composed of(Bi) an ionomer, (Bii) particles of zinc oxide, and (Biii) particles ofcopper oxide. The composition has a methyl mercaptan odor suppressionvalue of greater than 45% as measured in accordance with ASTM D5504-12.

A. Olefin-Based Polymer

The present composition includes an olefin-based polymer. Theolefin-based polymer can be a propylene-based polymer or anethylene-based polymer. Non-limiting examples of propylene-based polymerinclude propylene copolymer, propylene homopolymer, and combinationsthereof. In an embodiment, the propylene-based polymer is apropylene/α-olefin copolymer. Non-limiting examples of suitableα-olefins include C₂ and C₄-C₂₀ α-olefins, or C₄-C₁₀ α-olefins, or C₄-C₈α-olefins. Representative α-olefins include ethylene, 1-butene,1-pentene, 1-hexene, 1-heptene and 1-octene.

In an embodiment, the propylene/α-olefin copolymer is apropylene/ethylene copolymer containing greater than 50 wt % unitsderived from propylene, or from 51 wt %, or 55 wt %, or 60 wt % to 70 wt%, or 80 wt %, or 90 wt %, or 95 wt %, or 99 wt % units derived frompropylene, based on the weight of the propylene/ethylene copolymer. Thepropylene/ethylene copolymer contains a reciprocal amount of unitsderived from ethylene, or from less than 50 wt %, or 49 wt %, or 45 wt%, or 40 wt % to 30 wt %, or 20 wt %, or 10 wt %, or 5 wt %, or 1 wt %units derived from ethylene, based on the weight of thepropylene/ethylene copolymer.

In an embodiment, the olefin-based polymer is an ethylene-based polymer.The ethylene-based polymer can be an ethylene homopolymer or anethylene/α-olefin copolymer.

In an embodiment, the ethylene-based polymer is an ethylene/α-olefincopolymer. Non-limiting examples of suitable α-olefins include C₃-C₂₀α-olefins, or C₄-C₁₀ α-olefins, or C₄-C₈ α-olefins. Representativeα-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-hepteneand 1-octene.

In an embodiment, the ethylene/α-olefin copolymer is an LLDPE that is anethylene/C₄-C₈ α-olefin copolymer. The LLDPE has one, some, or all ofthe following properties:

(i) a density from 0.910 g/cc to 0.930 g/cc, or from 0.915 g/cc to 0.926g/cc; and/or

(ii) a melt index from 0.5 g/10 min, or 1.0 g/10 min, or 2.0 g/10 min to3.0 g/10 min, or 4.0 g/10 min, or 5.0 g/10 min.

B. Odor Suppressant

The present composition includes an odor suppressant. The odorsuppressant is composed of a (Bi) an ionomer, (Bii) particles of zincoxide, and (Biii) particles of copper oxide.

(Bi) Ionomer

The present composition includes an ionomer. An “ionomer,” as usedherein, is an ion-containing polymer. An “ion” is an atom that has anelectrical charge, either positive or negative. The ionomer has amajority weight percent (generally 85% to 90%) of repeating monomerunits that are non-ionic (non-polar), and a minority weight percent(generally 10% to 15%) of repeating comonomer units that are ionic, orpolar (i.e., positively-charged or negatively-charged). The positivecharges of the ionic groups attract the negative charges of the ionicgroups, creating ionic bonds. Ionomer resins exhibit what is known as“reversible crosslinking” behavior, i.e. when an ionomer is heated, thepolymer chains have increased mobility, and the ionic bonds cannot stayintact because the positive charges and negative charges are pulled awayfrom each other.

Non-limiting examples of the monomers and comonomers from which anionomer is derived include a copolymer of at least one alpha-olefin andat least one ethylenically unsaturated carboxylic acid and/or anhydride.Non-limiting examples of suitable alpha-olefins include ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and3-methylbutene. Non-limiting examples of suitable carboxylic acids andanhydrides include acrylic acid, methacrylic acid, ethacrylic acid,maleic acid, fumaric acid, and maleic anhydride.

In an embodiment, the ionomer is a copolymer of ethylene and methacrylicacid.

In an embodiment, the ionomer is a copolymer of ethylene and acrylicacid.

In an embodiment, the ionomer is a metal ionomer. A “metal ionomer,” asused herein, refers to a copolymer based on a metal salt of a copolymerof an alpha-olefin and an ethylenically unsaturated carboxylic acidand/or anhydride. The metal ionomer may be fully or partiallyneutralized by a metal ion. Non-limiting examples of metals suitable forneutralizing an ionomer include the alkali metals, i.e., cations such assodium, lithium, and potassium; alkaline earth metals, i.e., cationssuch as calcium, magnesium; and transition metals such as zinc. Anon-limiting example of a metal ionomer is Surlyn® 8660, which is asodium salt of an ethylene and methacrylic acid copolymer, availablefrom Dow-DuPont.

In an embodiment, the metal ionomer is a zinc ionomer. The term “zincionomer,” (or “ZnI/O”) as used herein, refers to a copolymer based on azinc salt of a copolymer of ethylene and a vinyl comonomer withcarboxylic acid/or anhydride. Non-limiting examples of suitablecomonomer having vinyl comonomer with an acid group includemethyl/methacrylic acid, vinyl acrylic acid, methacrylate, n-butylacrylic acid, and acrylic acid.

Non-limiting examples of suitable zinc ionomer include zinc salt ofethylene/acrylic acid comonomer, zinc salt ofethylene/methyl-methacrylic acid copolymer, zinc salt of ethylene/vinylacrylic acid copolymer, zinc salt of ethylene/methacrylate copolymer,zinc salt of ethylene/n-butyl acrylic acid copolymer, and anycombination thereof.

In an embodiment, the zinc ionomer is a zinc salt of ethylene/acrylicacid copolymer. Non-limiting examples of a suitable zinc ionomer includeSurlyn® 9150, which is a zinc salt of an ethylene and methacrylic acidcopolymer, available from Dow-DuPont.

B(ii) Particles of Zinc Oxide

The odor suppressant includes particles of zinc oxide (or “ZnO”). TheZnO particles have a D50 particle size from 100 nm to 3000 nm, a surfacearea from 1 m²/g to less than 10 m²/g, and a porosity less than 0.020m³/g.

In an embodiment, the ZnO particles have one, some, or all of thefollowing properties (i)-(iii) below:

(i) a particle size D50 from 100 nm, or 200 nm, or 300 nm, or 400 nm to500 nm, or 600 nm, or 700 nm, or 800 nm, or 900 nm, or 1000 nm, or 2000nm, or 3000 nm; and/or

(ii) a surface area from 1 m²/g, or 2 m²/g, or 3 m²/g, or 4 m²/g to 5m²/g, or 6 m²/g, or 7 m²/g, or 8 m²/g, or 9 m²/g; and/or

(iii) a porosity from 0.005 m³/g, or 0.006 m³/g, or 0.008 m³/g, or 0.010m³/g to 0.012 m³/g, or 0.013 m³/g, or 0.015 m³/g, or less than 0.020m³/g.

Non-limiting examples of suitable ZnO particles include 800HSA (ZincOxide, LLC), ZnO micropowder (US Research Nanomaterials), and Zoco102(Zochem, Inc.).

(Biii) Particles of Copper Oxide

The odor suppressant also includes particles of copper oxide. The copperoxide can be either “Cu₂O” (copper I oxide) or “CuO” (copper II oxide),or a mix of both. In an embodiment, the copper oxide particles have aD50 particle size from 100 nm to 3000 nm and a surface area from 1 m²/gto less than 10 m²/g. Bounded by no particular theory, it is believedthat the copper oxide particles contribute as a sulfur scavenger forhydrogen sulfide and mercaptans in particular.

In an embodiment, the copper oxide particles have a particle size D50from 100 nm, or 200 nm, or 300 nm, or 400 nm to 500 nm, or 600 nm, or700 nm, or 800 nm, or 900 nm, or 1000 nm, or 2000 nm, or 3000 nm.Non-limiting examples of suitable copper oxide particles include Cu₂O325 mesh powder and CuO 325 mesh powder available from Reade AdvancedMaterials.

C. Composition

The present composition includes (A) from 85 wt % to 99.5 wt % of theolefin-based polymer and (B) from 15 wt % to 0.5 wt % of the odorsuppressant, based on total weight of the composition (hereafter,Composition 1). The odor suppressant is mixed, or otherwise blended,into the olefin-based polymer matrix, and is a blend of (Bi) an ionomer,(Bii) particles of zinc oxide, and (Biii) particles of copper oxide. Thecomposition has an odor suppression value of greater than 45%. In anembodiment, the composition has an odor suppression value from 46%, or49%, or 50% or 60% or 70% to 75%, or 80%, or 85%, or 90%.

The ZnI/O (Bi) is present in component (B) in an amount of 1 to 90 wt %based on the total weight of component (B). The ratio of ZnO to ZnI/O(hereafter “ZnO to ZnI/O ratio”) is from 3:1 to 1:7 based on the totalweight of the odor suppressant (B). The ZnO to ZnI/O ratio can be from3:1, or 2:1, or 1:1 to 1:2, or 1:3, or 1:4, or 1:5, or 1:6, or 1:7. Theparticles of copper oxide (Biii) are present in component (B) in anamount of from 0.01 wt % to 30 wt % based on the total weight ofcomponent (B). The particles of copper oxide can be copper (I) oxide(Cu₂O), copper (II) oxide (CuO), or a mix of both. In an embodiment, theweight percent ratio between the ionomer (Bi), the zinc oxide (Bii), andthe copper oxide (Biii) is from 150:100:1 to 2.9:2.5:1 based on thetotal weight of the odor suppressant (B) (hereafter, Composition 1).

In an embodiment, the weight percent ratio between the ionomer (Bi), thezinc oxide (Bii), and the copper oxide (Biii) is from 100:75:1 to3:2.5:1 based on the total weight of the odor suppressant (B).

In an embodiment, the present composition includes from 85 wt %, or 90wt % to 95 wt %, or 97 wt %, 99 wt %, or 99.4 wt %, or 99.5 wt %component (A) that is an ethylene-based polymer. The present compositionincludes a reciprocal amount of the odor suppressant, component (B), orfrom 15 wt %, or 10 wt % to 5 wt %, or 3 wt %, 1 wt %, or 0.6 wt %, or0.5 wt % odor suppressant wherein Zn 1/O to ZnO to Cu₂O ratio is from12.5:12.5:1 to 2.5:2.5:1. The odor suppressant (B) can be any odorsuppressant as previously disclosed herein (hereafter, Composition 2).

The composition (i.e. Composition 1 and/or Composition 2) has an odorsuppression value from 46%, or 50%, or 60%, or 70% to 75%, or 80%, or85%, or 90%.

While the combination of ZnO and ionomer improve OSV for methylmercaptan, the addition of copper oxide, and in particular Cu₂O, hasbeen observed to further improve overall OSV. In fact, Applicantsurprisingly discovered that the addition of from 0.01 wt % to 0.1 wt %of Cu₂O to a ZnO/ionomer odor suppressing composition (based on thetotal weight of odor suppressant composition (B), for example) can morethan double the OSV performance compared to ZnO/ionomer odor suppressingcompositions that lack the copper oxide particles.

D. Blend

Components (A) and (B) are mixed, or otherwise blended, together to formthe present composition so that the particles of zinc oxide and theparticles of copper oxide are (i) dispersed within the olefin-basedpolymer (A) and/or (i) dispersed within the ionomer (Bi).

In an embodiment, the present composition is produced as an odor controlmasterbatch wherein component (B) is formed by dispersing the zinc oxideparticles (Bii) and the copper oxide particles (Biii) into the ionomer(Bi). The dispersing may be accomplished by physical mixing and/or meltblending of components (Bi), (Bii), and (Biii) in order to uniformlydisperse the particles (zinc oxide and copper oxide) throughout theionomer. The resultant component (B) is subsequently mixed, or otherwiseblended, with the olefin-based polymer, component (A). The mixing ofcomponent (B) and component (A) may be accomplished by physical mixingand/or melt blending (hereafter odor control masterbatch 1).

In an embodiment, the present composition is produced as an odor controlmasterbatch by dispersing the zinc oxide particles (Bii) into theionomer (Bi). The dispersing may be accomplished by physical mixingand/or melt blending of components (Bi) and (Bii) in order to uniformlydisperse the zinc particles throughout the ionomer (Bi) (“Bi-Biiblend”). The Bi-Bii blend and the copper oxide particles aresubsequently added to the olefin-based polymer component (A) by physicalmixing and/or melt blending to form the present composition of ahomogeneous blend of olefin-based polymer (A), ionomer (Bi), zinc oxideparticles (Bii), and copper oxide particles (Biii). (hereafter odorcontrol masterbatch 2)

In an embodiment, the present composition is produced as an odor controlmasterbatch by mixing the ionomer (Bi), the zinc oxide particles (Bii),the copper oxide particles (Biii) and the olefin-based polymer (A). Themixing may be accomplished by physical mixing and/or melt blending ofcomponents (A), (Bi), (Bii), and (Biii) in order to uniformly dispersethe ionomer (Bi), the zinc oxide particles (Bii), and the copper oxideparticles (Biii) throughout the olefin-based polymer (A) (hereafter odorcontrol masterbatch 3).

In an embodiment, the present composition is produced as an odor controlmasterbatch by mixing the ionomer (Bi), the zinc oxide particles (Bii),and the olefin-based polymer (A). The mixing may be accomplished byphysical mixing and/or melt blending of components (Bi), (Bii), and (A)in order to uniformly disperse (Bi) and (Bii) throughout (A) (hereafter,A-Bi-Bii blend). Copper oxide particles (Biii) are mixed with component(A). The mixing may be accomplished by physically mixing and/or meltblending in order to uniformly disperse the copper oxide particles(Biii) into (A) (hereafter, A-Biii blend). The A-Bi-Bii blend is thenmixed with the A-Biii blend. The mixing may be accomplished by physicalmixing and/or melt blending to form a homogeneous composition composedof olefin-based polymer (A), ionomer (Bi), zinc oxide particles (Bii),and copper oxide particles (Biii) (hereafter, odor control masterbatch4).

In an embodiment, the odor control masterbatch (i.e., any of odorcontrol masterbatch 1, 2, 3, or 4) includes from 20 wt % to 30 wt %ionomer, from 20 wt % to 30 wt % particles of zinc oxide, from 5 wt % to15 wt % particles of copper oxide, and from 30 wt % to 60 wt % LLDPE,with the aggregate of the components amounting to 100 wt % odor controlcomposition.

E. Applications

The present composition may be used in any application wherein apolymeric material, and an olefin-based polymer in particular, isexposed to mercaptans, H₂S, disulfides or amines. Non-limiting examplesof suitable applications for the present composition include trashliners, hygiene articles, poultry diapers, ostomy bags, mattresses,mattress covers, poultry packaging, automotive interior parts, carpetfibers, and carpet backing.

In an embodiment, the composition is formed into a film. The film can bea stand-alone monolayer film. Alternatively, the film can be a layer ofa multilayer film. The composition can be any composition as disclosedherein, with component (A) and odor suppressant (B), such as Composition1 or Composition 2, for example. The film includes the presentcomposition that is an odor control composition, the present compositioncomposed of (A) from 85 wt % to 99.5 wt % of an olefin-based polymer and(B) from 15 wt % to 0.5 wt % of the odor suppressant. The odorsuppressant is a blend composed of (i) an ionomer (for example, a zincionomer), (ii) particles of zinc oxide, and (iii) particles of copper(I) oxide or copper (II) oxide. The zinc oxide particles have a D50particle size from 100 nm to 3000 nm, a surface area from 1 m²/g to 9m²/g, and a porosity less than 0.020 m³/g. The composition has a methylmercaptan odor suppression value of greater than 45%. In an embodiment,the film has an odor suppression value from 46%, or 50%, or 60%, or 70%to 75% or 80%, or 85%, or 90%.

In an embodiment, the odor control composition formed into a filmincludes Cu₂O particles that are 325 mesh.

By way of example, and not limitation, some embodiments of the presentdisclosure will now be described in detail in the following Examples.

EXAMPLES

Materials used in the examples are provided in Table 1 below.

TABLE 1 Material/Description Properties Source Ethylene/octene 0.9 meltflow rate (I2) (g/10 min) The Dow (LLDPE 1) 0.923 g/cc Chemical CompanyZnO 800HSA ZnO D50 particle size 3000 nm; density = 5.61 g/cc; ZincOxide, LLC Zinc Oxide Porosity 0.0131 g/m³, surface area 4.46 m²/gmicro-powder (ZnO-1) Zinc Oxide ZnO D50 particle size 500 nm; density =5.61 g/cc; 500 nm (US micro-powder Porosity 0.008 m³/g, surface area3.36 m²/g Research (ZnO-2) Nanomaterials) Zoco102 ZnO D50 particle size200 nm; density = 5.61 g/cc; Zochem, Inc. Zinc Oxide Porosity 0.012m³/g, surface area 4.4 m²/g micro-powder (ZnO-3) Ampacet 110069 70 wt %TiO₂ Ampacet White PE MB in Carrier Resin LLDPE (MI 2.3, d- 0.917 g/cc)Corporation Titanium dioxide Masterbatch Specific gravity: 2.03 (TiO₂)Masterbatch Surlyn ® 9150 Ethylene/Methacrylic Acid Copolymer, zinccation Dow-DuPont (Zinc Ionomer) Density 0.970 g/cc, melt flow 4.5 g/10min Cu₂O 325 mesh Reade Advanced Materials

1. Films

Master batch processing. Two master batches were prepared to easefeeding the odor suppressing compositions into a subsequent film line.The master batches were prepared on a Coperion ZSK 26 twin screwextruder using a general purpose screw. The residence time of materialwas controlled by the screw design, feed rate of 20 lbs/hr, and a screwspeed of 300 revolutions per minute (RPM). No oil was injected. Therewas no side arm feeder. No vacuum was pulled. The compounded materialwas sent through a water bath before being cut by a strand cutpelletizer. After collection the pelletized materials were N₂ purged,then sealed in an aluminum bag.

The composition of the first master batch (MB1) was 50 wt % LLDPE 1, 25wt % ZnO, and 25 wt % Suryn 9150. The composition of the second masterbatch (MB2) was 90 wt % LLDPE 1 and 10 wt % Cu₂O. Examples and counterexample formulations were generated using the appropriate amount of pureLLDPE 1, MB1 and MB2 to achieve the target weight % of each compositionlisted.

TABLE 2 Blown film line process parameters Films without Filmscontaining Parameter Units TiO₂ MB TiO₂ MB Takeoff m/min 15 15 Layflatcm 23.5 23.5 Frostline cm 14 14 B.U.R ratio 2.5 2.5 Die gap mm 2.0 2.0Melt temperature - Ext. A ° C. 218 218 Melt temperature - Ext. B ° C.226 226 Melt temperature - Ext. C ° C. 215 215 RPM - Ext. A rpm 51 51RPM - Ext. B rpm 50 50 RPM - Ext. C rpm 32 32 Total Output kg/hr 8.8 8.8Film Total Thickness mm 0.023 0.056

2. Odor Suppression

The compositions of comparative samples (CS) and inventive examples (IE)are shown in Table 3.

The odor suppression values (OSV) for are provided in Table 3 below.Concentrations were measured using the reference sample (CS 1) as thecalibration standard after two days, concentrations in the referencesample might change after two days, so the concentrations in the samplesshould be considered as the relative change to the reference sample.

TABLE 3 Odor Suppression Values and Blown Film Properties OSV of MethylMercaptan Sample Components Methyl Mercaptan OSV (%) CS 1 99% LLDPE 1 +1% TiO₂ MB 12 CS 2 97.5% LLDPE 1 + 2.5% TiO₂ MB 2 CS 3 99% LLDPE 1 + 0.5wt % ZnO + 0.5 wt % Zinc Ionomer 28 CS 4 97.5% LLDPE 1 + 1.25 wt % ZnO +1.25 wt % Zinc Ionomer 44 IE 1 97.4% LLDPE 1 + 1.25 wt % ZnO + 1.25 wt %Zinc Ionomer + 0.1% Cu₂O 80 IE 2 98.9% LLDPE 1 + 0.5 wt % ZnO + 0.5 wt %Zinc Ionomer + 0.1% Cu₂O 64 IE 3 99.4% LLDPE 1 + 0.25 wt % ZnO + 0.25 wt% Zinc Ionomer + 0.1% Cu₂O 49 Zinc ionomer used in Table 3 is Surlyn ®9150 *TiO₂ MB—titanium dioxide masterbatch 70 wt % TiO₂ powder in 30 wt% LLDPE carrier, added for white color

In Table 3, component amounts for each sample yield 100 wt % totalsample composition. It can readily be observed that the ZnO/zinc ionomercombination is effective in improving OSV as compared to a compositionthat lacks any odor suppressing technology by comparing the OSV for CS 3(28%) to the OSVs for CS 1 & 2 (12% and 2% respectively). However, it issurprising to see that although Cu₂O is added at very low loadings aspart of the present odor suppressant (i.e., at <10% of the combinationof ZnO, zinc ionomer, and Cu₂O in IE2), it can further improve the OSVto 64% as compared to CS 3 OSV of 28%, (i.e., the sample with zincionomer and ZnO, and without Cu₂O present). The addition of Cu₂Ounexpectedly allows for a reduction in ZnO/zinc ionomer concentrationsby 50% in the composition while maintaining an OSV that is almost 50%higher than the ZnO/zinc ionomer combination that does not have Cu₂Opresent, as can be observed by comparing the OSV for IE3 (49%) to theOSV of CS3 (28%). It is further observed that the ZnO/zinc ionomercombination still exhibits a significant influence on OSV in that higherloadings of these materials in combination with 0.1 wt % Cu₂O exhibitsthe highest OSV of the inventive examples IE1 (80%) and IE2 (64%) shownin Table 3.

It is specifically intended that the present disclosure not be limitedto the embodiments and illustrations contained herein, but includemodified forms of those embodiments including portions of theembodiments and combinations of elements of different embodiments ascome within the scope of the following claims.

The invention claimed is:
 1. A composition comprising: (A) from 85 wt %to 99.5 wt % of an olefin-based polymer; (B) from 15 wt % to 0.5 wt % ofan odor suppressant comprising a blend of (i) an ionomer; (ii) particlesof zinc oxide; (iii) from 0.01 wt % to 0.1 wt % of particles of copper(I) oxide, based on the total weight of the odor suppressant; and thecomposition has a methyl mercaptan odor suppression value of greaterthan 45% as measured in accordance with ASTM D5504-12.
 2. Thecomposition of claim 1, wherein the olefin-based polymer is anethylene-based polymer.
 3. The composition of claim 2, wherein theethylene-based polymer is an ethylene/C₄-C₈ α-olefin copolymer having amelt index (I₂) from 0.5 g/10 min to 15 g/10 min and a density of 0.910g/cc to 0.930 g/cc.
 4. The composition of claim 1, wherein the ionomeris a metal ionomer.
 5. The composition of claim 1, wherein the ionomeris a zinc ionomer.
 6. The composition of claim 5, wherein the ionomer isa zinc salt of a polymer selected from the group ofethylene/methyl-methacrylic acid, ethylene/vinyl acrylic acid,ethylene/methacrylate, ethylene/n-butyl acrylic acid, and ethyleneacrylic acid.
 7. The composition of claim 1, wherein the particles ofzinc oxide have a D50 particle size from 100 nm to 3000 nm.
 8. Thecomposition of claim 1, wherein the particles of copper oxide areselected from the group of copper (I) oxide and copper (II) oxide. 9.The composition of claim 8, wherein the particles of copper oxide have aD50 particle size from 100 nm to 3000 nm.
 10. The composition of claim1, wherein the weight percent ratio between the ionomer (Bi) the zincoxide (Bii) and the copper oxide (Biii) is from 150:100:1 to 2.9:2.5:1.11. A film comprising: a composition comprising: (A) from 85 wt % to99.5 wt % of an olefin-based polymer; (B) from 15 wt % to 0.5 wt % of anodor suppressant comprising a blend of (i) an ionomer; (ii) particles ofzinc oxide; (iii) from 0.01 wt % to 0.1 wt % of particles of copper (I)oxide, based on the total weight of the odor suppressant; and thecomposition has a methyl mercaptan odor suppression value of greaterthan 45% as measured in accordance with ASTM D5504-12.
 12. Thecomposition of claim 1, wherein the ratio of (Bii) particles of zincoxide to (Bi) the ionomer is from 3:1 to 1:7, based on the total weightof the odor suppressant (B).
 13. The composition of claim 10, whereinthe weight percent ratio between the ionomer (Bi) the zinc oxide (Bii)and the copper (I) oxide (Biii) is from 12.5:12.5:1 to 2.5:2.5:1.